Spool and coil body



Aprifi 1%,1935.

H. D. asamszne SPOOL AND COIL BODY Filed April 27, 1935 In venion- JYCUZSZJ-BQfl berg Patented Apr. 16, w 1935 UNITED STATES PATENT OFFICE granted;

3 Claims.

The invention relates to spools, and particularly to spools and coil bodies or bobbins, for electrical coils.

Such a coil body may comprise a tubular, round or prismatic central portion provided with a flange at either end. It is usually made from a plurality of suitably shaped pieces which are assembled, and finally glued and pressed together to form a unit. There are several methods known for manufacturing such coil bodies. However, expenses per coil are relatively high due to the necessity for expensive machinery and relatively complicated manual assembly labor. In some cases, depending upon the particular structure of the bodies, there is also a considerable waste of material. Another important point shouldbe taken into account, namely, the performance of such glued coil bodies when subjected to certain operating con ditions, particularly in the presence of humidity and high temperatures. The glued portions may warp or crack and affect the coil detrimentally. Difiiculties occur frequently in the case of such coils placed in high tension circuits. The glue may deteriorate and cause or support electrolytic actionwith attendant or subsequent trouble to the performance of the apparatus. Consideration must also be given to the space available on such a spool for accommodating the windings. Since some of the space is taken up by the glued overlapping flanges or portions thereof and by the assembled and glued tubular barrel of the coil body, it is apparent that the required winding space can only be achieved by increasing the over-all dimensions of the coil body. In other words, most of these glued and pressed spools cause at least somewaste of winding or assembly space. This is particularly of importance in the case of devices, such as transformer coils and the like, and in the case of apparatus using a plurality of coils in a crowded space.

My invention, which is illustrated in several embodiments in the accompanying drawings, eliminates the above noted and other drawbacks. I use, in certain embodiments, a minimum number of stamped or punched parts, formed with a view to keep down the stamping 'costs. These parts are simply assembled toform the desired spool. No gluing is required. The individual parts are all so designed and formed with.

interlocking serrations as to render support and rigidity to the assembly. -A simple operation may be added to press certain parts into place viously may be used tor forming my novel spools.

The cost of making such a spool is practically limited to theexpense for the material and the punching or stamping operation. There is no rule or limitation as to'the time of making the spools. They may be made immediately prior to their use or may be made ahead of their use, and they may be stored or shipped as desired. The resulting product will be found to be superior to the spools now known and in use. The cost of central tubular portion or barrel for the spool} Fig. 4 shows a perspective yiew of the assembled spool; and

Figs. 5, 6, 7, and 8 illustrate corresponding elements for a spool according to another embodiment of my invention.

Referring now to the drawing, Figs. 1 to 4, inclusive, it will be seen that each of the flanges for the embodiment shown in these flgures may be formed according to the structure shown in Fig. l. The body of the flange which may be made of a suitable fiat insulating material is indicated by the numeral II. The flange is provided with a central opening having a number of serrations or looking teeth such as indicated by the numeral l2. Numerals l3 and M indicate holes or openings ior taking terminal clips or the like. If desired the'terminals may be provided directly on the flanges simultaneously with the punching operation.

The blank for forming the central portion or .barrel of the coil body is particularly shown in Figs. 2 and 3. It comprises a punched or stamped strip i5 made of suitable insulating material.

At one end of the strip is a locking notch it and at the other end of the strip is, a locking tooth it. On either side of the strip are a number of locking notches such as it and 69. On the face of the blank it are provided a number of transversal grooves such as it, 2i and 22. It should be observed that I have provided as many notches on either side or the'blanlr it as there are pro jeotions or looking teeth. in the center of the corresponding flange tor the barrel.

The blank is folded along the transverse grooves 20, 2| and 22 to term a tubular prismatic barrel. The locking tooth 'il will then register and engage the locking notch N. This will'prevent a 2 lateral distortion of the tubular barrel. The folding points will be clean and smooth due to the transverse grooves provided on the face of the blank which relieve any surface tension in.

the material upon folding of the same.

After the barrel is formed as above described,

' projections are punched out from the material in the flanges I I, one on either side, are attached to the barrel as is particularly shown in Fig. 4. It will be seen that the locking serrations or teeth on each side of the barrel engage the corresponding serrations in the central opening of the corresponding flanges. The result is a rigid self-supporting assembly such as is shown in Fig. 4. The depth of the notches I8-l on the sides of the barrel blank corresponds substantially to the thickness of the flange material and, accordingly, the face'of the flange on the assembled spool will be smooth and free of projections or bulges. This preserves space for assembly. A lateral displacement or distortion of the barrel is excluded'due to the serrations at the ends of the blank I5 which register and engage one another. Nevertheless, there will be a natural tension in the material acting outwardly, with the result that a press'ure is exerted upon the supporting walls of the openings in theflanges. This also will contribute toward providing strength and rigidity to the spool. It

may be desirable in the case of certain spools be provided at a very low cost. The flanges are then definitely locked inany direction on the barrel and the spool is ready for use. Attention is called to the simplicity of the spool structure and to the economy in the use of material which results in a spool having maximum effective winding space and minimum effective assembly .dimensions.-

d It will be seen uponexamining the blanks l l' and i5 shown in Figs. 1 and 2 that stamping and punching tools are required for the manufacture of these blanks which might be relatively ex-- pensive due to the serrations or looking teeth on the sides'and ends of the blank 55 and the serrations or locking teeth within the blank ll.

The embodiment shown in the Figs. 5 to 8, inclusive, eliminates the necessity for such relatively expensive tools employed in the manufacture of the blanks; I use in this embodiment a flange suchas the one shown in Fig. 5 designated by the numeral 23. This flange is again made of a suitable not material with an opening Ethaving straight and'smooth walls. Holes, such as 25 and 26 may again be provided in theblank of the flange for the'purpose of receiving terminals, or, terminals may be secured to these blanks directly.

It will beseen that the provision of the simple' opening 24 necessitates but a simple punching tool and the manufacture of this blank will, therefore, be cheaper than the blank shown in Fig. l.

The barrel for this embodiment of the invention is formed from a blank 21 as shown in Figs; 6 and 7. Theends'of-this blank are again providedwith serrations or looking notches and teeth indicatedby the reference numerals 28 and 23 but the sidesare in the form or straight line edges.

Transverse grooves at the placeslwhere the blank the opening of v is to be folded are also provided as indicatedat 30, 3| and 32. In order to determine the assembly of the flanges on the completely folded barrel, I also provide on either side of the blank 21a number of bosses or projections indicated by the nu- I merals '33 to 36 and 3'1 to 60, respectively. These in the assembly shown in Fig. 8. It should be noted that the locking tooth 29' is approximately of the thickness of the material and that the depth of the notch 28 is accordingly dimensioned.

The same is true with regard to the corresponding locking provisions on the, previously discussed blank as indicated in connection with the description. of the previous embodiment. The spool will I again be self-supporting without any gluing.

Additional rigidity and strength may be provided by preserving-the smooth straight edges of the barrel on either end into andagainst the material grooves 89 of the flanges by means, of a simple punching comprisinga barrel portion consisting of a single member made of flat insulating material, locking means on each end of said member for-interlocking said ends to hold said barrel against lateral v distortion, locking means on the body of said barrel; near the sides thereof and a flange made of flat insulating material for attachment to each side of said barrel engaging and interlocking with said second named locking means to .hold said spool against longitudinal and radial distortion.

2. A self-supporting spool for electrical coils of the class described, comprising a single insulating I member forming a strip, serrations at each end of said strip, said strip beingshaped end to end to form the central barrel of said spool with said serrations interlocking to hold said formed barrel against distortion, locking means on each side of said barrel, said locking means projecting from the body of said barrel and being integral there with, and a flange made of flat insulating material secured on each side of said barrel and held by said locking means.

3. A prismatic spool for electrical coils of the 

